ABSTRACT: The principal objective of the Endothelial Biophysical Analysis and Imaging Core is to provide PPG investiga- tors with a complete range of expertise, training, equipment, and data analysis tools to obtain nano-to-micro scale biophysical information pertaining to the cellular and molecular basis of endothelial cell (EC) barrier regu- lation. Core D personnel and equipment will allow PPG scientists to image 3D structures, evaluate physical and chemical properties and define perturbant-induced real-time changes in the structures and activity of cells and subcellular constituents, including membranes, cytoskeletal networks, and cell-matrix and cell-cell junc- tions. This Endothelial Biophysical Analysis and Imaging Core supports the PPG's three research projects with quantitative microscopy related to atomic force microscopy (AFM), light fluorescence microscopy, total internal reflection fluorescence (TIRF) microscopy, dynamic fluorescence imaging, mechanical measurements of cells (traction force microscopy) and super-resolution microscopy to allow observation of cellular organelles (e.g., cortical cytoskeleton, junctional complexes, focal adhesions and lamellipodia) in great detail (3D). Core D will also interact with each Project and with Core B (Proteome and Genome Core) to culture endothelial cells engi- neered to express different MLCK, cortactin, EVL, c-Abl, integrin ?4 and paxillin transgenes with specific SNP or post-translational modification mutations and measure various biophysical forces (TFM and AFM). The Core also offers access to experienced use of the complete resources of the University of Arizona Imaging Core Facilities that includes state-of-the-art atomic force microscopes integrated with high-resolution fluores- cence microscopy systems for simultaneous multimodal correlative studies. This Core will also make use of the common resources available at Arizona Research Laboratories. The Biophysical Imaging, led by Carol C. Gregorio, PhD, includes personnel and laboratory facilities for a wide range dynamic fluorescence imaging, fabrication, and mechanobiophysics. Core D personnel have professional experience spanning the fields of high resolution imaging and examining physical and chemical properties, including mechanobiophysics, and various scanning probe microscopies. All Core D experiments will be conducted at the University of Arizona in Tucson.